Windows/Mac only: Freeware applications iSproggler (Windows) and iScrobbler (Mac) upload your iTunes and iPod listening habits to the popular music recommendation service Last.fm. Any Last.fm junkie knows that the most important part of the service is that the music you listen to gets "scrobbled" (i.e., sent to Last.fm's database to track your listening habits), and if you do most of your listening with your iPod, you want to make sure those listens get synced up, too. Both applications integrate with iTunes and iPods on their respective OS, so if you've been interested in giving Last.fm a try, I'd recommend either.